The invention relates to an arrangement for rotatable adjustment of a cap on an eyepiece housing.
An arrangement such as this is disclosed in DE 101 39 173 C1. In the known arrangement, the pins are arranged fixed in the eyepiece housing. The pins are screwed and fixed so far into the eyepiece housing that their heads are at least approximately at the same distance from the longitudinal axis of the eyepiece housing.
The cap which is placed onto the eyepiece housing has grooves which rise in the axial direction on its inner face, and in which latching depressions are arranged at defined points. The distance between the sliding bases of the grooves and of the latching depressions and the longitudinal axis of the eyepiece housing is somewhat shorter than the distance between the heads of the pins and the longitudinal axis. The cap is made of a deformable material, so that the fitting of the sliding bases and of the latching depressions under the heads of the pins when the cap is fitted and the heads of the pins engage in the groove can be absorbed by slight deformation of the cap. On the other hand, the deformation advantageously results in prestressing between the cap and the pins, which on the one hand allows sliding rotation of the cap while on the other hand allowing it to latch securely into the latching depressions.
In practice, it has been found that if the eyepiece housing and the caps have relatively small diameters, the normal manufacturing and assembly tolerances influence the freedom of movement of the rotary adjustment in a non-uniform manner. There may be noticeable play in the latching positions. The deformation of the cap partially results in sliding and jamming. These disadvantages can be overcome only by individual matching of all of the tolerances. The matching process is highly time-consuming.